For this tutorial you are going to need:

20/20
Filter Factory D

This is the image I have used for this tutorial:

Open this in PSP and go to effects, plug-in filters, filter
factory d, dimensia and use these settings:

This is what you should end up with after applying the
dimensia filter:

Save this picture. Open it in 20/20 and apply the tile effect
(image, tile effect).

Voila......your background !!! :-)